When a Printed Circuit Board (PCB) is tested in a laboratory by bringing a conventional test pin in contact thereon, because a test pad on the PCB has a small size (for example, with a diameter of 0.3 mm), it is difficult to make the test pin and the test pad in contact, and especially when the test is performed for a long time, a failure in the test is easily caused by shaking; when the test is performed on multiple test pads at the same time, it requires a lot of people to work collaboratively; and during the test, there is often a case that because a test pad is far from a ground pad and a ground clamp of a test tool has a wire with a limited length, it causes a clutter interference to a test signal. These factors result in an inefficient test on the PCB.